1. Field of the Invention
The present invention relates to an inner pressure indicator of cuff attached to a tracheostomy tube with a cuff or a endotracheal tube with a cuff that are used for the emergency or long term breathing regulation, for the breathing regulation of an unconscious patient or for the breathing regulation used at general anesthesia. Especially, the present invention relates to an inner pressure indicator, which indicates not only the inner pressure of a cuff attached to a tracheostomy tube with a cuff or an endotracheal tube with a cuff but also regulates inner pressure of the cuff.
2. Description of the Prior Art
Usually, for the purpose of emergency or long term breathing regulation, for the breathing regulation of an unconscious patient or for the purpose to maintain trachea line at general anesthesia, various kinds of endotracheal tubes to be inserted into trachea from larynx or tracheostomy tubes to be inserted in the incised part of trachea have been developed. Among these tubes, a tracheostomy tube with a cuff or an endotracheal tube with a cuff that use a cuff of double tube structure are already developed. These kinds of tracheostomy tube with a cuff or endotracheal tube with a cuff can effectively prevent the air leaking from the gap between tube and trachea or the flowing in of saliva or vomited substance into trachea by the presence of a cuff. The most important point of said tracheostomy tube with a cuff or said endotracheal tube with a cuff is to regulate the inner pressure of cuff, and when the inner pressure of cuff is too low, the purpose of the cuff cannot be fully achieved, on the contrary, when the inner pressure of cuff is too high, it oppresses vascular in tracheal mucous membrane and makes trachea ischemic condition, and causes ulcer, bleeding and a granuloma further causes tracheal-stenosis or tracheo-malscia after the removal of the tube. In general, for the purpose to prevent the occurrence of said problems, it is desirable to maintain the inner pressure of a cuff within 25–30 mmHG. In the present invention, the inner pressure of a cuff is indicated by gage pressure, and gage pressure can be calculated by subtracting the atmosphere pressure (760 mmHG) from absolute inner pressure of cuff. At the actual use of these tubes by connection to a breathing device, usually the pressure of 100 mmHg is temporarily added to a cuff to confirm that there is no air leak from the breathing device. And at this procedure, it is important to regulate the inner pressure of the cuff not abnormally high pressure to be added.
Usually, in the actual use of a tracheostomy tube with a cuff or a endotracheal tube with a cuff, for the purpose to regulate the inner pressure of the cuff, following method is carried out. That is, air or physiological salt solution is poured into the cuff and inflate the cuff by a syringe, then the syringe is removed from the tube, the inner pressure of the cuff is measured by a pressure gage and the inner pressure of the cuff is regulated. Or, by regulating the amount of air at the inflation procedure of the cuff, the inner pressure of the cuff is adjusted. As mentioned above, in a case of the conventional tracheostomy tube with a cuff or endotracheal tube with a cuff, since the regulation procedure of the inner pressure and the measurement of the inner pressure are carried out separately, the using of these tubes are not easy and very complicated. To solve said problem, a device that can carry out simultaneously the regulation of inner pressure of cuff and the measurement of the inner pressure of cuff is developed. For example, a method to place a flat balloon between an air introduction hole and a tracheostomy tube or a endotracheal tube and to indicate the inner pressure of cuff by observing the inflation degree of the balloon, or a method to connect a tube for pressing between an air introduction hole and a tracheostomy tube or a endotracheal tube and to indicate the inner pressure of cuff are developed.
However, in the cases of these devices for indicating inner pressure of cuff, since the inner pressure is not displayed by numerical value, the accurate regulation of the inner pressure can not be expected. The increment and the reduction of the inner pressure by observing the inflation degree of balloon is a very difficult and complicated work, further the structure of the device becomes very complicated and needs electric source, and still more have a problem of rising the price of these devices.